'\" et
.TH UTIME "3P" 2017 "IEEE/The Open Group" "POSIX Programmer's Manual"
.\"
.SH PROLOG
This manual page is part of the POSIX Programmer's Manual.
The Linux implementation of this interface may differ (consult
the corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
.\"
.SH NAME
utime
\(em set file access and modification times
.SH SYNOPSIS
.LP
.nf
#include <utime.h>
.P
int utime(const char *\fIpath\fP, const struct utimbuf *\fItimes\fP);
.fi
.SH DESCRIPTION
The
\fIutime\fR()
function shall set the access and modification times of the file named
by the
.IR path
argument.
.P
If
.IR times
is a null pointer, the access and modification times of the file shall
be set to the current time. The effective user ID of the process shall
match the owner of the file, or the process has write permission to the
file or has appropriate privileges, to use
\fIutime\fR()
in this manner.
.P
If
.IR times
is not a null pointer,
.IR times
shall be interpreted as a pointer to a
.BR utimbuf
structure and the access and modification times shall be set to the
values contained in the designated structure. Only a process with
the effective user ID equal to the user ID of the file or a process with
appropriate privileges may use
\fIutime\fR()
this way.
.P
The
.BR utimbuf
structure is defined in the
.IR <utime.h> 
header. The times in the structure
.BR utimbuf
are measured in seconds since the Epoch.
.P
Upon successful completion, the
\fIutime\fR()
function shall mark the last file status change timestamp
for update; see
.IR <sys/stat.h> .
.SH "RETURN VALUE"
Upon successful completion, 0 shall be returned. Otherwise, \-1
shall be returned and
.IR errno
shall be set to indicate the error, and the file times shall not be
affected.
.SH ERRORS
The
\fIutime\fR()
function shall fail if:
.TP
.BR EACCES
Search permission is denied by a component of the path prefix; or the
.IR times
argument is a null pointer and the effective user ID of the process
does not match the owner of the file, the process does not have write
permission for the file, and the process does not have appropriate
privileges.
.TP
.BR ELOOP
A loop exists in symbolic links encountered during resolution of the
.IR path
argument.
.TP
.BR ENAMETOOLONG
.br
The length of a component of a pathname is longer than
{NAME_MAX}.
.TP
.BR ENOENT
A component of
.IR path
does not name an existing file or
.IR path
is an empty string.
.TP
.BR ENOTDIR
A component of the path prefix names an existing file that is neither
a directory nor a symbolic link to a directory, or the
.IR path
argument contains at least one non-\c
<slash>
character and ends with one or more trailing
<slash>
characters and the last pathname component names an existing file
that is neither a directory nor a symbolic link to a directory.
.TP
.BR EPERM
The
.IR times
argument is not a null pointer and the effective user ID of the calling
process does not match the owner of the file and the calling process
does not have appropriate privileges.
.TP
.BR EROFS
The file system containing the file is read-only.
.br
.P
The
\fIutime\fR()
function may fail if:
.TP
.BR ELOOP
More than
{SYMLOOP_MAX}
symbolic links were encountered during resolution of the
.IR path
argument.
.TP
.BR ENAMETOOLONG
.br
The length of a pathname exceeds
{PATH_MAX},
or pathname resolution of a symbolic link produced an intermediate
result with a length that exceeds
{PATH_MAX}.
.LP
.IR "The following sections are informative."
.SH EXAMPLES
None.
.SH "APPLICATION USAGE"
Since the
.BR utimbuf
structure only contains
.BR time_t
variables and is not accurate to fractions of a second,
applications should use the
\fIutimensat\fR()
function instead of the obsolescent
\fIutime\fR()
function.
.SH RATIONALE
The
.IR actime
structure member must be present so that an application may set it,
even though an implementation may ignore it and not change the last data
access timestamp on the file. If an application intends to leave one of
the times of a file unchanged while changing the other, it should use
\fIstat\fR()
or
\fIfstat\fR()
to retrieve the file's
.IR st_atim
and
.IR st_mtim
parameters, set
.IR actime
and
.IR modtime
in the buffer, and change one of them before making the
\fIutime\fR()
call.
.SH "FUTURE DIRECTIONS"
The
\fIutime\fR()
function may be removed in a future version.
.SH "SEE ALSO"
.IR "\fIfstat\fR\^(\|)",
.IR "\fIfstatat\fR\^(\|)",
.IR "\fIfutimens\fR\^(\|)"
.P
The Base Definitions volume of POSIX.1\(hy2017,
.IR "\fB<sys_stat.h>\fP",
.IR "\fB<utime.h>\fP"
.\"
.SH COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1-2017, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, 2018 Edition,
Copyright (C) 2018 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group.
In the event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online at
http://www.opengroup.org/unix/online.html .
.PP
Any typographical or formatting errors that appear
in this page are most likely
to have been introduced during the conversion of the source files to
man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .
